Prop antifouling

philip_stevens

philip_stevens

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live near Saint Ives, Cornwall.
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Reading a post on Sailnet.com about prop anti-fouling, one reply was the use of "Pettit Zinc Coat Barnacle Barrier", of which he said he had good results.

Does anyone know where this can be bought from in the UK - other than eBay and posted from the USA?

It sounds as though it works.

I have had varying success in either polishing or anti-fouling the prop. For a couple of years, I brought the prop home and gave it a really good shine. This lasted about half the season before it looked like a white calcium covered object. This year, I gave it a 2 coats of hard AF, and other than where it flaked off, didn't look too bad. There was some fouling that effected the revs/speed.

If this stuff is as good as the post says, and I can get some from within the UK, I will give it a go next summer season.

So, anyone come across this in the UK?

EDIT....more info on Pettit product and another product from MG Duff.

On Pettit - 93 percent pure zinc in the dried film.
"Zinc Coat Barnacle Barrier 1792 provides easy to use aerosol spray protection for bare metals including steel, stainless steel, cast iron, copper, bronze, galvanized steel, and lead. It forms an excellent bond to underwater metals and running gear, and inhibits corrosion on these surfaces. Zinc Coat Barnacle Barrier’s smooth, hard surface will self-clean in service, and can be used above or below the waterline. The dried film of Zinc Coat contains 93% pure zinc. Not for use on aluminum surfaces."

On Zingaspray - contains 92% Zinc in the dry film (pure to 99,995%). Zinga (not spray) is 96% (±1%) by weight, with a purity of 99,995% in the dry film
From www.zinga-uk.com/files/MarineTechBrief_vs3.pdf
"• In some marine environments barnacles do not like the taste of zinc and many other forms of marine life do not like adhering to the Zinga surface because of the low current passing between the zinc and the substrate."

So it looks as though I will be using Zingaspray next season. Anyone else used it??
 
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Looks intersting!
You can buy zinc sprays in the UK which I have used successfully on domestic applications. (gates )
This one is supplied by an anode company:
http://www.mgduff.co.uk/zingard.html?gclid=CI-o9Mal_awCFYIPfAodXF_HTg
I also have noted that you don't get barnacles on the zinc anodes whereas they seem to like copper ground plates.
So...it may all begin to make sense!!!!
 
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Can this Zingard stuff be used on Bronze props safely? I have tried all sort of things to keep the barni's off and it all lasts about half a season. Perhaps this is the answer?
 
I just paint mine with the same a/f as I use on the hull. Seems as successful/unsuccessful as other things I have tried, eg polishing, lanolin, Zebo, beeswax.
 
Ripster said:
Can this Zingard stuff be used on Bronze props safely? I have tried all sort of things to keep the barni's off and it all lasts about half a season. Perhaps this is the answer?
Click to expand...

It looks as though the Zingard is the same or similar to the Pettit zinc spray, and that says it can be applied to "steel, stainless steel, cast iron, copper, bronze, galvanized steel, and lead."

So I am hoping the Zingard (MG Duff) can be applied the same.

As said, I also have never noticed barnacles on the zinc anode. Yes, makes sense now, but seems like it must be the high % zinc spray.
 
Agree I have never seen barnies on the zinc anodes but, equally, my zinc anodes get a hard white coating by the end of the season. Is this likely to be a problem with zinc on the prop?
 
alahol2 said:
Agree I have never seen barnies on the zinc anodes but, equally, my zinc anodes get a hard white coating by the end of the season. Is this likely to be a problem with zinc on the prop?
Click to expand...

I understood that if a hard white coating was on an anode it was not working. They are sacrificial anodes-they give up their metal before the expensive bits of boat. The action of doing this causes them to pit and stay free of surface coatings. It is concievable that your boat is naturaly protected and no galvanic corrosion is taking place, therefore the white coating- be nice if it is!
 
Yes, Some of the anode is eroded and stays 'zinc coloured' but the edges get the white coating. I assume the anode is protecting things. I get through the pear anode on the hull every couple of seasons.
I just wondered if the zinc spray would be eroding galvanically, would get the white coating or stay zinc coloured.
 
Thinking it through, the Zingard is used as a cold galvanising so it should act as a sacrificial anodic coating. If it acts as one of the elements in a galvanic couple, then it should erode slowly, probably reacting with the stainless of the prop shaft. If it doesn't erode then it can be expected to form a fine white coating, just like the larger anode, but this will have little effect on the props performance compared with fouling. Mind you, that is based on the assumption that it will have electrical continuity with the substrate - the prop. I seem to recall that granular metals suspended in a carrier medium are insulators, like Coppercoat being compatible with steel hulls. If it insulates, then surely that will prevent corrosion anyway?

Anyone know for sure?

Rob.
 
How can you expect the zinc on a zinc coated propeller not to erode, and yet expect the zinc anode beside it to erode?
 
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